Multiscale Modeling of Polymer Based Nanomaterials

摘要

In materials design and engineering there is a need for fundamental information that spans large scales of time and distances, from the quantum chemical nature of interactions to the macroscopic mechanical and electrical properties. In order to acquire technologically relevant information the most efficient modeling methodology for each time and length scale should be used. We have developed a new methodology using a synergy of ab initio quantum chemical (QC), atomistic molecular dynamics (MD), coarse grained molecular (CGM), and material point (MPM) computer simulation methods to explore materials behavior across these scales of interest. In this method it is important to represent the key physics (degrees of freedom) at each level explicitly while maintaining the influence of the other degrees of freedom implicitly through systematic parameterization or mapping. The mapping of important information between these different techniques is bidirectional and makes it possible to calculate the thermodynamic, dynamic, and electrical properties of materials with novel nanostructures. In order to illustrate these principles we will present a model of self assembling Poly(ethylene oxide) (PEO) decorated fullerenes in aqueous solutions which shows preferential formation of crystalline or linear aggregates depending on the density and orientation of the PEO tethers. Using this methodology we will also show how we can overcome the heterogeneous energy and time scales involved in modeling the micelle formation of triblock copolymers in aqueous solutions. Finally we will present our results showing calculations of viscoelastic properties of nanocomposites.